Synthesis of Hydroximoyl Chlorides from Aldoximes and Benzyltrimethylammonium Tetrachloroiodate (BTMA ICl4)

Benzyltrimethylammonium tetrachloroiodate (BTMA ICl4) acts as a convenient reagent to convert aldoximes to hydroximoyl chlorides by a simple procedure. When an aldoxime is treated with BTMA ICl4 in dichloromethane, the suspension of BTMA ICl4 shortly diasappears as the reaction proceeds. The resulting BTMA ICl2 can be precipitated out by adding diethyl ether. Not only stable aromatic and heteroaromatic hydroximoyl chlorides can be isolated by this method but also rather unstable aliphatic hydroximoyl chlorides can be generated in situ. 1,3-Dipole trapping with a dipolarophile is performed in one flask and in some cases the chlorination is successfully performed in the presence of dipolarophile and triethylamine. Effect of MS 4A has been examined.